They have just been marketed recently in new and more creative ways. Benjamin Moore Regal, the old stuff of ten years ago, had self priming characteristics, and it said right on the back of the can that it could be used as its own primer on raw sheetrock or patches. That was ten years ago. It was more of a convenience thing historically than a celebrated best practice. The current generation of paint lines from different manufacturers have taken that handy little tidbit of performance info and stamped it right on the front of the cans.
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Paint - Wikipedia
Its attractive color and sheen are significant but secondary. Paint companies must create products that are both pleasing to the eye and likely to last. How Paint Works When paint dries, it produces a water-resistant layer that shields your house from most weather damage. Colorants consist of tiny particles joined by the binding agent, which also attaches them to walls and other features. A substance with binding properties — such as alkyd, vinyl, acrylic, or latex — is typically included in the production of paint. All of these except alkyd consist primarily of water and result in water-based paint.
Clark+Kensington Semi-Gloss Designer White Acrylic Latex Paint and Primer 1 gal.
Watercolors as applied with a brush Since the time of the Renaissance , siccative drying oil paints, primarily linseed oil , have been the most commonly used kind of paints in fine art applications; oil paint is still common today. However, in the 20th century, water-based paints, including watercolors and acrylic paints , became very popular with the development of acrylic and other latex paints. Milk paints also called casein , where the medium is derived from the natural emulsion that is milk , were popular in the 19th century and are still available today.
The low pressure used to draw the paint out of the gun significantly reduces the amount of over-spray produced by traditional compressed air paint guns. This lower pressure works well with oil-based paints and finishes but presents some obstacles when using thicker, heavier latex paint. These obstacles can be overcome with a bit of extra equipment and paint preparation. Paint Preparation Quality latex paint is significantly thicker than traditional finishes and must be thinned before it is useful as a spray finish.